Magnification power changing mechanism for view-and-range-finder having rotatable galilean type optical system



y 1959 MASAMICHI KAKUNODATE ,8

MAGNIFICATIQN POWER CHANGING MECHANISM FOR VIEW-ANIFRANGE-FINDER HAVINGROTATABLE GALILEAN TYPE OPTICAL SYSTEM Filed Jan. 3, 1957 2 sheets-sheet1 (e CI:

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y 8, 1959 MASAMICHI KAKUNODATE 2,896,500

NAGNIFICATION POWER CHANGING uscmursu FOR vmwmo-amcs-nunm 1mm: ROTATABLEmum/m TYPE OPTICAL sys'rsm Filed Jan. 3, 1957 2 Sheets-Sheet 2 FIG. 8

IN V EN TOR.

BY M M H M rI/uomm villi-ml! United States Patent MAGNIFICATION rowanCHANGING MECHA- NISM ron VIEW-AND-RANGE-FINDER HAVING l ltgglATABLEGALILEAN TYPE OPTICAL SYS- Masamichi Kakunodate, Tokyo,-Japan, assignorto Canon glamera Company, Inc., Tokyo, Japan, a corporation of spamApplication January 3, 1957, Serial No. 632,315

f Claims priority, application Japan April 21, 1956 6 Claims. (Cl.88-1.5)

The instant invention relates to an improvement in a mechanism forchanging the magnification power of a viewand range-finder having arotatable Galilean type optical system.

An object of the instant invention is to provide an effective, usefuland simplified mechanism to change the camera. g

By the magnifying power changing mechanism of the.

instant invention, asimple structure is obtained for the desired purposeby 'providingbut few members occupy ing no appreciable space inthecamera body. By so doing a nice appearance is imparted to the camera,since the indicator dial of the view-finder is inside the range- -findercover and the indicator feading window is formed at the topof the cameracasing. -Incomparison with conventional mechanisms having the indicatordial on Fig.6 is a sectional side view along the line VI--VI of Fig. 5;

Fig. 7 is a plan view of the indicator reading window;

Fig. 8 is a plan view of the device according to the instant inventionwith its top cover removed;

Fig. 9 is a sectional plan view along line IXIX of Fig. 5; and

Fig. 10 is a sectional side view along line X--X of Fig. 9.

Referring to Fig. l, the rangefinder of the so-called image coincidencetype comprises a prism a having a semi-transparent mirror and a movableprism b. A rotatable, variable power optical system C is inserted at therear of semi-transparent prism a. The rotatable, variable power opticalsystem comprises a Galilean optical system consisting of a concave lensd and a convex lens e aligned on the same optical axis x and located ateach side of the cubic block 0 respectively. As shown in Figures 2 and4, a negative lens provided with a rectangular reflecting mirror g atits marginal portion, and a flat glass provided with a frame mark f onits central portion, are cemented respectively to the upper and lowerfaces of block c. A virtual image of frame mark f is formed byreflecting mirror g when viewed along another optical axis y from thebottom to the top in Figure 3. Such variable power optical system isaligned with the optical axis x of the viewand range-finder. The mode ofoperation is as follows: When the axis z, perpendicular to the axes xand y of the optical block c, is aligned with the semi-transparent prisma, a unit magnification (or life size) image is produced correspondingto the standard focal length objective used with the camera, of whichthe top surface of the camera'casing, the device accord- 1 ing to theinstant invention is quite unrestricted as to the .size of thecharacters to indicate the magnification of the viewfinder in theparticularsetting andprovides a sufficiently large dial carryingreasonably large characters' which can easily be distinguished.Characters showing' the-focal lengths of interchangeable lens may bemarked directly on the indicator.

A prior known variable-magnification viewfinder employs a verticalrotatable shaft to support the optical system, but my research hasdemonstrated that a horizontal rotatable shaft is more convenient forthis purpose.

By such arrangement of the shaft, additional'valuable,

space ,is obtained around the optical system for positioning thereinother small mechanisms required in the camera, or such space providesmore room for theoptical the image field is framed .by the reflectedlight frame; when the optical system is positioned as shown in Figure 2,a wider field results corresponding to a wide angle objective; and whenthe optical system is rotated 180 degrees about axisy, that is from theposition shown in Figure 2 to that of Figure 4, the magnification ischanged to correspond to a telephoto objective, and, in its specialcase, as shown in this embodiment, this high magnification power may beutilized for range finding purposes. Such optical system is quite commonand well known to those skilled in the art. Thus the desired magnifyingpower for the image field corresponding to an interchangeable lens canbe obtained; for. instance, image fields corresponding to 35 mm. and 50mm. focal length lenses and high power for range finding.

' Now the turret mechanism of rotatable, variable power according'tothis invention will be set forth in detail.

Referring to Figure l, the negative lens 11 is a rectangle correspondingto the shape of the picture to be photographed. If the optic-a1 systemis rotated about a vertical axis, the rotation is obstructed by the endof large lens system itself to enable a more preferable arrangementthereof.

The novel characteristics I consider characteristic of the instantinvention are set forth with particularity in the appended claims. Theinvention itself, both as to its organization and mode of operation,together with additional objects, features andadvantages thereof, willbest be understood from the following description when read inconjunction with the accompanying drawings, in which:

Fig. 1 is a plan view of the optical systemof a preferred viewandrange-finder according to the instant invention;

Figs. 2, 3 and 4 are plan views of therotatable variable power opticalsystem in its respective positions;

Fig. 5 is a sectional view of the device along line V-V of Figure 8;

d and semi-transparent prism a. Such objection will be eliminated byrotating the optical system about a horizontal axis, axis y of Figure 2,since the upper and lower edges of the large lens d do not touch prisma. On the other hand, if a lens of the same size as lens d is employedin the horizontally rotating mechanism, lens d may be located furtheroutwardly from its center of ro-- tation than in the vertically rotatingdevice. This applies also to the other lens e, and consequently, thesetwo lenses comprising a Galilean telescope, may be adequately spacedfrom each other. Such increased and adequate spacing between the twolenses allows the use of a larger radius of curvature in each lenselement, when identical optical performance is desired, as compared toan optical system with less spacing between the lenses. Needless to say,the larger radii of curvature of the optical elements decrease theaberrations more than do smaller radii of curvature. The space about theoptical system won by the use of horizontally rotating mechanisms may befurther utilized for other small mechanisms; for example, a parallaxcorrecting mechanism may be inserted between the eyepiece F and theoptical system in Figure 8, but such mechanism is not here described asit is no part of the invention of the present application. Thehorizontal shaft 2 is rotatably mounted to a base frame 3 in a bearing4. The horizontal shaft 2 is disposed in engagement with a verticalshaft 5 rotatably mounted in base frame 3 by screw gears 6 and 7,meshing with'each other and affixed to shafts 2 and 5 respectively. By aprotruding part of an operating disk or knurled ring 10 rigidly securedto vertical shafts 5 from'the back of the camera body through an opening9 provided in therear portion of rangefinder chamber 8, the variablepower optical system is rotated around said horizontal shaft 2. A clickstop mechanism consisting of a spring plate 11, a steel ball 12, anopening 13' in spring 11 to receive the ball, and grooves 13 on therotatable member 29 alfixed to one end of the optical system, isprovidedto assure proper positioning of the optical system as shown inFigure 8. A gear 16 is adjustably attached by means of a screw 17 on thetop of vertical shaft 5 supported by bearing plate 14 which is affixedto base frame 3 by screw 15. Anindicator dial 19 is integral with asleeve 20 and a gear 21 and rotatably supported on a stub shaft 18 onhearing plate 14 by means of screw 25, gear 21 meshing with gear 16. Onthe upper surface of indicator dial 19, characters, for example 35, 50and RF to show the respective focal lengths of the objective lenses orthe magnifying power of the viewfinder, are carved thereon to indicatethe magnifying power of the variable power optical system C. A window oraperture 23 is provided in the camera casing 22 in alignment with thecharacters on indicator dial 19. Aperture 23 is of such size as just torender visible only one of the indicating characters at a time, and mayalternatively be designed with a relatively large transparent disk 24,such as a glass or the like, atfixed onto the camera casing 22 withwindow or aperture 23 thereof transparent to read the character, withthe remaining part thereof being opaque or semi-transparent. Therelative position of the rotating optical system and the indicator dialin respect of window 23 may be adjusted by means of adjustable gear 16on vertical shaft 5 by screw 17, or, in the alternative, the adjustmentmay be made by means of gear 21.

Referring to Figs. 8 and 9, a horizontal shaft 26 is coaxial with ahorizontal shaft 2 forming an extension thereof. The horizontal shaft 26is' integral with disk 29 carrying the peripheral detent 13 for theclick stop. The two shafts are adjustably connected by means of aconnecting screw 27 and journaled in base frame 3 and bearing 4.Vertical shaft 5 is journaled in base frame 3 and bearing plate 14.Horizontal shaft 2 is coupled with vertical shaft 5 by screw gears 6 and7 secured to the respective shafts. An operating disk or knurled ring 10is rigidly secured to vertical shaft 5 and has a peripheral portionprojecting outside the back casing of the camera through opening 9provided at the rear of rangefinder chamber 8. The variable opticalsystem c is attached to rotatable member 29. Plate spring 11 is afiixedto base frame 3 by means of bent supports 3 and screws 31 to facerotatable member 29, the spring plate 11 having an opening or a grooveto receive small steel ball 12 between it and rotating member 29. Steelball 12 is arranged on engagement with opening 13 to function as a clickstop mechanism.

The operation of the device is as follows: Viewing; through the findereye piece F, the user rotates knurled disk 10 with the thumb of his lefthand to select the power of the rotatable optical system C, lightlyfeeling the opposition of the click stop mechanism. Since thefiotographer can operate the device without moving the rest of his handor his other fingers while holding the camera in his hand to photographa subject, adjustment (1 the magnifying power can readily be done atease at the users original posture; the mechanism according to theinstant invention thus provides snapshot performance and satisfies theaforesaid objects. Furthermore it will be noted that the turretmechanism with a horizontal shaft results in a remarkably simple andsturdy structure by arranging horizontal shaft 2, vertical shaft 5 andscrew gears 6 and 7 thereon in the out 01f portion 32 (see Fig. 9) ofbase frame 3 described above.

The photographer, viewing the subject through eyepiece F, turns knurleddisk 10 clockwise until he hears a click if he wants highly accuratelytomeasure the distance he may now do so sincetherange finderis at its highmagnification RF-mark. Then, when hetums the knurled disk in theopposite directionjuntil he hears: another click, indi eating thepositioning of the middle power of 50 mm. objective, he obtains thecorrect view for a 50 mm. photo graphic objective. While the RF-mark isprovided for the special requirement of most accurate measuring, theview and range finder work excellently also at the 50- mark and at the35-mark positions for, respectively, 50 mm. and 35 mm. photographicobjectives.

While there has beendescribed what is presently considered to be thepreferred embodiment of this invention, it will be obvious to thoseskilled departing from the inventiomand it is, therefore, aimed in theappended claims to cover all such change'sland I modifications as fallthe invention.

the true spirit and scope of- What I claim is: i I V I v 1. Amagnification power changing mechanism for" rotation of the support,each telescope having a different and predetermined'magnifying power, arotatable verti-. cal shaft, gearing interconnecting the horizontal andverlf tical shafts, a knurled disc integral with the vertical shaft,-

the camera casing defining an aperture through which a peripheral regionof the knurled disk extends, an indicator dial connected to the top ofthe vertical shaft, an

eyepiece with which the'telescopes are alignable to view an object, anda plurality of indiciaequal in number to the plurality of telescopes onone faceof the dial for indicating the particular telescope of the.plurality of aligned with the eyepiece. v

2. A magnification power changing mechanism according to claim 1 inwhich a circular member about the horizontal shaft is attached to thesupport, the peripheral region of the circular member has at least twodetents, a formed plate spring has both its ends attached to the camerabody, and a metal ball is biased by the plate spring against thecircular member to enter the detents on rotation of the support to aposition in which a telescope is aligned with the eyepiece.

3. A magnification power changing mechanism according to cliam 1 havingmeans for angularly adjusting the indicator dial relative to thevertical shaft.

4. A magnification power changing mechanism 'accord- 2 ing to claim 1 inwhich the dialis supported on a stub shaft and being spatially fixedagainst movement along its axis.

6. A magnification power changing mechanism for in the art thatvariouschanges and modificationsmay be made therein withoutshaft, asupport integral combined view and range finders in a camera casing,comprising a rotatable first horizontal shaft spatially fixed againstmovement along its axis, a first gear integral with the first horizontalshaft, a second horizontal shaft aligned with the first horizontalshaft, threaded means interconnecting the first and second horizontalshafts with the disc extends, a vertical stub shaft adjacent the topregion second horizontal shaft axially distant from the first horizontalshaft a controllable distance, a disk integral with the outer end regionof the second horizontal shaft, a plurality of detents in the peripheralregion of the disk, a steel ball, a formed spring having its end affixedto the camera casing and its free intermediate region biasing the steelball to enter a detent of the plurality, a carrier aflixed to the disk,a plurality of Gal-lilean telescopes arranged on the carrier angularlyto each other with the optical axis of each telescope passing throughthe horizontal axis on which the carrier rotates, each telescope havinga different and predetermined magnifying power, an eyepiece with whichthe telescopes are individually alignable to view an object, the numberin the plurality of detents being equal to the number in the pluralityof telescopes and each detent being so positioned as to be aligned with,and partially entered by, the steel ball when the eyepiece is alignedwith a telescope, a rotatable vertical shaft, a second gear integralwith the vertical shaft of the vertical shaft, a sleeve integral with athird gear rotatable on the stub shaft, an indicating dial detachablyconnected to the top of the sleeve, a plurality of markings on the upperface of the dial of a number equal to the number of the telescopes, adial window in the camera casing of a size to expose but one marking ata time, and a fourth gear rotatable with, and angularly adjustablerelative to, the vertical shaft so that the corresponding markingappears in the dial window on alignment of the corresponding telescopewith eyepiece on rotating the knurled disk.

References Cited in the file of this patent UNITED STATES PATENTS2,108,751 Kuppenbcnder Feb. 15, 1938 2,529,944 Houck Nov. 14, 19502,552,940 Cornut May 15, 1951 FOREIGN PATENTS 838,391 Germany May 15,1952 1,017,937 France Oct. 1, 1952

